Gonad development and reproductive hormones of invasive silver carp (Hypophthalmichthys molitrix) in the Illinois River.

Gonad development and reproductive hormones of invasive silver carp (Hypophthalmichthys molitrix) in the Illinois River. Biol Reprod. 2019 Nov 11;: Authors: Tucker EK, Zurliene ME, Suski CD, Nowak RA Abstract Reproduction is a major component of an animal's life history strategy. Species with plasticity in their reproductive biology are likely to be successful as an invasive species, as they can adapt their reproductive effort during various phases of a biological invasion. Silver carp (Hypophthalmicthys molitrix), an invasive cyprinid in North America, display wide variation in reproductive strategies across both their native and introduced ranges, though the specifics of silver carp reproduction in the Illinois River have not been established. We assessed reproductive status using histological and endocrinological methods in silver carp between April-October 2018, with additional histological data from August-October 2017. Here we show that female silver carp are batch spawners with asynchronous, indeterminate oocyte recruitment, while male silver carp utilize a determinate pattern of spermatogenesis which ceases in the early summer. High plasma testosterone levels in females could be responsible for regulating oocyte development. Our results suggest that silver carp have high spawning activity in the early summer (May-June), but outside of the peak spawning period, female silver carp can maintain spawning-capable status by adjusti...
Source: Biology of Reproduction - Category: Reproduction Medicine Authors: Tags: Biol Reprod Source Type: research